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Metabolic Myopathy
Published in Maher Kurdi, Neuromuscular Pathology Made Easy, 2021
McArdle disease is a type-V glycogen storage disease that commonly occurs in young patients with recurrent myoglobinuria and exertional cramps. The vacuoles are very fine and smaller than the ones described in Pompe disease. It is associated with absent phosphorylase enzymes in muscle fibers.
Basic Microbiology
Published in Philip A. Geis, Cosmetic Microbiology, 2020
Inclusions and vacuoles—These very small membrane-bound structures represent micro-organization of nutrients and waste for storage and transport. In the case of gas vacuoles, some bacteria in aqueous environments use these for buoyancy.
Endosomal and Lysosomal Electrophysiology
Published in Bruno Gasnier, Michael X. Zhu, Ion and Molecule Transport in Lysosomes, 2020
Xiaoli Zhang, Mingxue Gu, Meiqin Hu, Yexin Yang, Haoxing Xu
Although whole-endolysosome recordings provide a direct analysis of lysosomal membranes, one should be aware that the recording conditions are quite simplified compared to intact cells. First, genetically or chemically enlarged vacuoles may contain membranes from non-lysosomal intracellular organelles (Wang et al., 2017). Second, the endolysosome enlargement process may result in changes of membrane lipid composition. Third, the lysosome isolation process may also cause a loss of interaction proteins and cytosolic factors. Fourth, the ionic environments are determined by pipette and bath solutions, but the real ionic compositions of lysosomes have not been accurately determined (Wang et al., 2012). Hence, complementary approaches are necessary to validate the conclusions that are drawn based on the whole-endolysosome patch-clamp method.
The possible protective role of vitamin C versus melatonin on potassium dichromate induced changes in rat thyroid gland: light and electron microscopic study
Published in Ultrastructural Pathology, 2023
Eman Saeed, Ahmed A. El-Mansy, Shireen A Mazroa, Amal M. Moustafa
Electron microscopic examination of the thyroid gland confirmed the toxic effect of potassium dichromate in group II. Thyroid follicles revealed areas of follicular hyperplasia. Ultrastructural changes were seen in the thyroid follicular cells in the form of shrunken heterochromatic nuclei with irregular nuclear membranes and wide perinuclear spaces. The apical surface of follicular cells revealed a partial loss of the apical microvilli. The cytoplasm of follicular cells exhibited dilated cisternae of rough endoplasmic reticulum, dilated Golgi apparatus, numerous lysosomes and degenerated mitochondria with loss of their cristae. The cytoplasm also contained extensive vacuoles of variable sizes and shapes in the affected cells. Similar results have been reported by Al Jameil et al., Khalil et al. and Jaeger et al.38–40 who demonstrated that potassium dichromate had highly cytotoxic effects on the cell through increased oxidative stress and DNA damage.
Phagocytosis: Phenotypically Simple Yet a Mechanistically Complex Process
Published in International Reviews of Immunology, 2020
The mTOR promotes vesicle fission from the phagosome in a vacuolar H+-adenosine triphosphatase ATPase (V-ATPase)-dependent manner, which occurs in parallel to the lysosome reformation from autophagolysosomes [342,343]. Thus, the macroendocytic vacuole formation during the late stage of phagocytosis or the entosis (the engulfment of live cells) involves the processing of large vacuoles by mTOR-dependent membrane fission mechanism. The inhibition of the mTOR signaling pathway increases the size of associated phagosomal vacuole that is closely apposed to the phagosome [344]. The identification of this vacuolar compartment will prove helpful to understand the subcellular trafficking involved in the destruction of phagocytosed anti-body opsonized cells or pathogens. The downstream mTOR signaling controlling the fission of phagolysosomes or autophagolysosomes is still not clear. However, an increased mTOR activity attenuates autophagy and generates proto-lysosomal tubules and vesicles, which extrude from autolysosomes These proto-lysosomal tubules and vesicles mature into functional lysosomes independent of IRAK1/4 (Interleukin-1 receptor-associated kinase 1 or 4) and TBK (TANK binding kinase) during TLR-mediated signaling in the presence of PI3K [345,346]. Hence, the phagocytic process is not merely to engulf the pathogens or dying cells but to digest them accordingly as per the need for the host to maintain the homeostasis.
Toxicity of differently sized and charged silver nanoparticles to yeast Saccharomyces cerevisiae BY4741: a nano-biointeraction perspective
Published in Nanotoxicology, 2019
Kaja Kasemets, Sandra Käosaar, Heiki Vija, Umberto Fascio, Paride Mantecca
TEM observations revealed that differently from bPEI-coated AgNPs, citrate-coated AgNPs and exposure to AgNO3 caused an increase in the size of vacuoles (Figure 9). Similar ultrastructure changes upon exposure to AgNO3 and citrate-coated AgNPs could indicate the same mode of action of these Ag compounds. Indeed, the toxicity of 10 and 80 nm citrate-coated AgNPs was explainable by the shed Ag ions (Figure 4, Supporting Information Table S1). Vacuoles in the yeast cells are the main vesicular transport target organelles, resembling the lysosomes of the mammalian cells, having a large variety of macromolecules degrading capacity but also proteins and ions storage function (Li and Kane 2009). Increase in the size of the vacuoles is characteristic stress-response of yeast at the ionic stress conditions (Li and Kane 2009). TEM observation of 10nAg-Cit, 80nAg-Cit, and, AgNO3 exposed cells showed the presence of the dark/black electron dense area in the vacuoles (border of the vacuoles, see the white arrows in Figure 9). Silver has a high affinity for the sulfur compounds (Eckhardt et al. 2013) and the formation of silver-thiol-groups-containing proteins complexes may cause the proteins misfolding, subsequent non-functionality and degradation in the vacuoles. Moreover, silver has also high affinity to the phosphorus compounds and yeast vacuoles contain a lot of phosphorous (Li and Kane 2009). Hypothetically these black electron-dense areas in the vacuoles (Figure 9) may contain Ag-protein and Ag-phosphorous complexes.